Interstitial Laser Therapy of Congenital VascularMalformations with MRI Guidance

Abstract

Summary Introduction: Extratruncular, infiltrating congenital vascular malformations (CVM) are found in all organ systems. Large substance defects and diffuse blood loss may occur during surgical removal. Thus, conservative and interventional procedures are also applied, one of them being interstitial laser therapy (ILT). Patients and methods: Forty children with deep CVM underwent interstitial laser therapy with open MRI. The laser light guide was introduced into the malformation with a titan puncture needle and the tissue was thermically damaged by adequate selection of the physical parameters of the Nd:YAG 1064-nm laser. Beside the high soft-tissue contrast, MRI has the advantage of thermosensibility. For online thermomonitoring, we used 3 time-optimized MR sequences with a maximal velocity of 1 image in 3 seconds. Results: Positioning of the puncture needle was excellent in all applications and thermomonitoring was successful in 89%. A reduction of the tumor volume was observed in 36 patients at the 6-week follow-up. The volume of the malformations was reduced to 76%, on the average. Clinical improvement was seen in 78% of the cases. One fifth of the children are presently without symptoms. Thermic skin damage in 2 cases and intracorporal bare fiber tip loss in 1 case was found to be a complication. Discussion: Process control is decisive for successful interstitial laser therapy. Beside the high soft tissue contrast, MRI is characterized by a thermosensibility which does not allow invasive registration of temperature changes provoced by ILT inside the body. Summary: The introduction of open MR systems has enabled access to patients and interactive management directly in the magnetic field. MR-controlled interstitial laser therapy has to be included in the differential treatment of complicated congenital vascular malformations.